What is the working principle of a mechanical transmission?
3 Answers
The working principle of a mechanical transmission includes the principles of manual transmission, automatic transmission, and AT transmission. Below are the relevant introductions: 1. Principle of manual transmission: By shifting the gear lever, the driving gear on the intermediate shaft is switched, and the combination of gears of different sizes with the power output shaft changes the torque and speed of the driving wheels. The engine's power input shaft is indirectly connected to the power output shaft through an intermediate shaft. 2. Principle of automatic transmission: An automatic transmission uses planetary gear mechanisms to change gears. It can automatically shift gears based on the degree of the accelerator pedal and changes in vehicle speed, while the driver only needs to control the speed by operating the accelerator pedal. 3. Working principle of AT transmission: The torque converter is the most distinctive component of an AT transmission. It directly inputs the engine's power and transmits torque while also serving as a clutch. The pump wheel drives the turbine to rotate through fluid, and by adding a guide wheel between the pump wheel and the turbine, the speed difference between the pump wheel and the turbine can be achieved through reaction force, enabling gear shifting and torque conversion.
The principle of a manual transmission is actually quite similar to bicycle gears. When the engine transmits power through the input shaft, those sets of large and small gears inside start performing. For example, in first gear, a small gear drives a large gear to rotate, making the engine spin fast while the wheels turn slowly—resulting in low speed but high torque, which is perfect for climbing hills or starting. As speed increases and you shift to fifth gear, it switches to a large gear driving a small gear, allowing the engine to run smoothly while the wheels spin rapidly, making it most fuel-efficient for highway driving. The synchronizer, a small but critical component, ensures the two gears synchronize their speeds before meshing during a shift, preventing grinding noises and gear damage. Those who drive manual transmissions best understand the art of switching gear ratios through the gear lever.
Think back to riding a geared bicycle as a kid: when starting off, you'd use the large chainring with the smallest rear cog - it's hard to pedal but gets you moving slowly. Once up to speed, you'd switch to the small chainring with larger rear cogs, where each pedal stroke carries you much farther. A car's transmission works on the same principle: the input shaft connects to the engine, the output shaft links to the wheels, with five or six sets of differently sized gear combinations in between. When shifting gears, pressing the clutch disengages the power, while moving the gear lever activates the shift fork to engage the target gear. Here, the synchronizer matches the rotational speeds of both gears to prevent jerking. Lower gears multiply torque like pedaling hard uphill on a bike, while higher gears are like cruising effortlessly on flat roads at speed. Structurally, it's just several shafts making gears dance together.
